The NRC Makes a Determination After Last Year’s Crane Collapse

Last year, the Arkansas Nuclear One facility experienced a tragic incident when a crane collapsed. One person was killed, eight were injured and important plant equipment was damaged. The NRC has now issued two “yellow” inspection findings as a result. The “yellow” means we found substantial safety significance related to the incident.

Workers were moving a massive component out of the plant’s turbine building when the incident occurred. Unit 1 was in a refueling outage at the time, with all of the fuel still in the reactor vessel. At the time, Entergy Operations declared a Notice of Unusual Event, the lowest of four emergency classifications used by the NRC, because the crane collapse caused a small explosion inside electrical cabinets. The damaged equipment caused a loss of off-site power. The NRC’s senior resident inspector had driven to the plant to personally survey the damage and monitor the licensee’s response from the plant’s control room.

Here’s why NRC decided the incident had substantial safety significance even though both plants were safely shut down and there was no radiological release or danger to the public: Emergency diesel generators were relied upon for six days to supply power to heat removal systems.

The falling turbine component damaged electrical cables needed to route power from an alternate AC power source to key plant systems at both units. This condition increased risk to the plant because alternate means of providing electrical power to key safety-related systems was not available using installed plant equipment in the event the diesels failed.

Unit 2, which was operating at full power, automatically shut down when a reactor coolant pump tripped due to vibrations caused when the heavy component fell and hit the turbine building floor. Unit 2 never completely lost offsite power, and there was a way to provide it with emergency power using the diesel generators.

The NRC conducted an Augmented Team Inspection. We prepared a detailed chronology of the event, evaluated the licensee actions in response, and assessed what may have contributed to the incident. (Worker safety issues are the responsibility of the Occupational Safety and Health Administration, which conducted an independent inspection of the incident.)

The NRC determined that the lifting assembly collapse was a result of the licensee’s failure to adequately review the assembly design and to do an appropriate load test.

We held a public meeting in Russellville, Ark., on May 9, 2013, to discuss the team’s initial findings. From its follow-up inspections, the NRC issued a preliminary red finding to Unit 1 and a preliminary yellow finding to Unit 2. These are documented in a March 24 inspection report.

NRC held a regulatory conference with Entergy officials on May 1, and after considering information provided by the licensee determined that “yellow” findings were appropriate to characterize the risk significance of the event for both Unit 1 and 2. The NRC will determine the right level of agency oversight for the facility and notify Entergy officials of the decision in a separate letter.

Victor Dricks
One key question is what will it take for the NRC, and especially NRC Region IV to issue RED “findings” since the above failures led to a death and multiple injuries, all because the Operator tried to cut corners?

The NRC should immediately issue RED “findings” upon a death or radioactive leak to the atmosphere!

NRC issues inspection findings based on their risk significance and effect on nuclear safety. In this case, it was determined “yellow” findings for Units 1 and 2 were appropriate to characterize the risk significance of the effects of the incident on the plant. Worker safety issues are the responsibility of the Occupational Safety and Health Administration, which conducted an independent investigation of the crane collapse and levied fines totaling $175,000 against Entergy Operations, a crane company and other firms in September 2013.

By the NRC only looking at nuclear safety (which should include loss of life if related to operating a NPP, the NRC is just making it easier for Utilities to slide between their various regulators, a situation that does affect nuclear safety for all those living close to NPP’s.

Thanks for the prompt response and perspective you provided Mr. Dricks. However, there does seem be a lack of red, yellow, or white findings. The vast bulk of findings are green or No Findings. And there are violations of NRC requirements that are not even written up in inspection reports. There are also Non- cited Violations. The system has way too many layers where stuff can be buried. I think people can relate quite well to green, yellow, and red. The vast bulk of NRC violations fall into the Green category. To the layman this sounds OK when in fact it is not OK but a violation of NRC requirements. Green should be used only when no violations of requirements are identified.

Here we are a year later and the focus of the utility seems to be on debating the safety significance of this tragic accident. You would think the proper focus would be on preventing such an accident in the future and sharing that information with the industry.

I have been reviewing this accident with interest. And have looked at the many of accident reports summaries , I am loath to down load the largest one. From what I can tell , and hearing the way the crane fell. The real reason the failure occurred was when the stator was being “turned” to lower into the train bay. Some of the centrifugal force in its turn was transferred to the crane twisting it imposing a lateral force spin on the four point structure), caused failure of one of the legs or just overwhelm the design at all four points. I look at that crane and basically those spindly legs and that one diagonal leg crossbeam(which again could part of the spin to either the lower or upper area of one leg. ) And go that crane was too weak for the job(weak legs) and its design (without an x cross-beam support) is inherently flawed. Am I correct in my assessment of the accident and the crane? (I think the legs should be twice as thick as they are and an X-beam support between the two legs of each pair.

Anyway , I see you asked for an update, here it is 3 years later , and there is nothing about it?

And y’all are correct to focus on the nuclear aspects, because this came alot closer to a serious accident than acknowledge. I read about the series of failures here and the broken fire main shorting out almost everything, Kinda close there. I was wondering more about the crane and crane operators aspect.
Dropping 500 tons can and will break almost anything. I’ve seen a few tons of metal drop and hit concrete and the “boom” alone is impressive, thrilling, and also a serious realization of how deadly it could be even without loss of life and injuries which occurred here.

Archives

Archives

Comments on blog posts do not represent official NRC communication, and links to internet sites other than the NRC website do not constitute the agency’s endorsement of that site’s content, policies or products. Please read our Disclaimer for more information.